Exponentially back off the time between message polling instead of doing it every two minutes.

src/components/navigation/www/navigation.jsx

@@ -27,7 +27,8 @@ class Navigation extends React.Component {
         super(props);
         bindAll(this, [
             'getProfileUrl',
-            'handleSearchSubmit'
+            'handleSearchSubmit',
+            'setupMessagePolling'
         ]);
         this.state = {
             messageCountIntervalId: -1 // javascript method interval id for getting messsage count.
@@ -35,27 +36,18 @@ class Navigation extends React.Component {
     }
     componentDidMount () {
         if (this.props.user) {
-            const intervalId = setInterval(() => {
+            // Setup polling for messages to start in 2 minutes.
-                this.props.getMessageCount(this.props.user.username);
+            setTimeout(this.setupMessagePolling.bind(this, 2), 2 * 60 * 1000);
-            }, 120000); // check for new messages every 2 mins.
-            this.setState({ // eslint-disable-line react/no-did-mount-set-state
-                messageCountIntervalId: intervalId
-            });
         }
     }
     componentDidUpdate (prevProps) {
         if (prevProps.user !== this.props.user) {
             this.props.handleCloseAccountNav();
             if (this.props.user) {
-                const intervalId = setInterval(() => {
+                setTimeout(this.setupMessagePolling.bind(this, 2), 2 * 60 * 1000);
-                    this.props.getMessageCount(this.props.user.username);
-                }, 120000); // check for new messages every 2 mins.
-                this.setState({ // eslint-disable-line react/no-did-update-set-state
-                    messageCountIntervalId: intervalId
-                });
             } else {
                 // clear message count check, and set to default id.
-                clearInterval(this.state.messageCountIntervalId);
+                clearTimeout(this.state.messageCountIntervalId);
                 this.props.setMessageCount(0);
                 this.setState({ // eslint-disable-line react/no-did-update-set-state
                     messageCountIntervalId: -1
@@ -66,7 +58,7 @@ class Navigation extends React.Component {
     componentWillUnmount () {
         // clear message interval if it exists
         if (this.state.messageCountIntervalId !== -1) {
-            clearInterval(this.state.messageCountIntervalId);
+            clearTimeout(this.state.messageCountIntervalId);
             this.props.setMessageCount(0);
             this.setState({
                 messageCountIntervalId: -1
@@ -77,6 +69,23 @@ class Navigation extends React.Component {
         if (!this.props.user) return;
         return `/users/${this.props.user.username}/`;
     }
+
+    setupMessagePolling (minutes) {
+        this.props.getMessageCount(this.props.user.username);
+        // We only poll if it has been less than 30 minutes.
+        // Chances of someone actively using the page for that long without
+        // a navigation is low.
+        if (minutes < 32) {
+            const nextFetch = minutes * 2;
+            const timeoutId = setTimeout(() => {
+                this.setupMessagePolling(nextFetch);
+            }, nextFetch * 60000);
+            this.setState({ // eslint-disable-line react/no-did-mount-set-state
+                messageCountIntervalId: timeoutId
+            });
+        }
+    }
+
     handleSearchSubmit (formData) {
         let targetUrl = '/search/projects';
         if (formData.q) {

test/unit/components/navigation.test.jsx

@@ -1,5 +1,5 @@
 const React = require('react');
-const {shallowWithIntl} = require('../../helpers/intl-helpers.jsx');
+const {shallowWithIntl, mountWithIntl} = require('../../helpers/intl-helpers.jsx');
 import configureStore from 'redux-mock-store';
 const Navigation = require('../../../src/components/navigation/www/navigation.jsx');
 const Registration = require('../../../src/components/registration/registration.jsx');
@@ -11,6 +11,7 @@ describe('Navigation', () => {
 
     beforeEach(() => {
         store = null;
+        jest.useFakeTimers();
     });
 
     const getNavigationWrapper = props => {
@@ -103,4 +104,88 @@ describe('Navigation', () => {
         navWrapper.find('a.registrationLink').simulate('click', {preventDefault () {}});
         expect(navInstance.props.handleClickRegistration).toHaveBeenCalled();
     });
+
+    test('Component sets up message polling when it mounts', () => {
+        store = mockStore({
+            navigation: {
+                registrationOpen: false
+            },
+            messageCount: {
+                messageCount: 5
+            }
+        });
+        const props = {
+            user: {
+                thumbnailUrl: 'scratch.mit.edu',
+                username: 'auser'
+            },
+            getMessageCount: jest.fn()
+        };
+        const intlWrapper = mountWithIntl(
+            <Navigation
+                {...props}
+            />, {context: {store},
+                childContextTypes: {store}
+            });
+
+        intlWrapper.children().find('Navigation')
+            .instance();
+        const twoMin = 2 * 60 * 1000;
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMin);
+        // Advance timers passed the intial two minutes.
+        jest.advanceTimersByTime(twoMin + 1);
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMin * 2);
+        expect(props.getMessageCount).toHaveBeenCalled();
+    });
+
+    test('SetupMessagePolling polls for messages 5 times', () => {
+        store = mockStore({
+            navigation: {
+                registrationOpen: false
+            },
+            messageCount: {
+                messageCount: 5
+            }
+        });
+        const props = {
+            user: {
+                thumbnailUrl: 'scratch.mit.edu',
+                username: 'auser'
+            },
+            getMessageCount: jest.fn()
+        };
+        const intlWrapper = mountWithIntl(
+            <Navigation
+                {...props}
+            />, {context: {store},
+                childContextTypes: {store}
+            });
+
+        const navInstance = intlWrapper.children().find('Navigation')
+            .instance();
+        // Clear the timers and mocks because componentDidMount
+        // has already called setupMessagePolling.
+        jest.clearAllTimers();
+        jest.clearAllMocks();
+
+        navInstance.setupMessagePolling(2);
+
+        // Check that we set the timeout to backoff exponentially
+        let minutes = 2 * 60 * 1000;
+        for (let count = 1; count < 5; ++count) {
+            jest.advanceTimersByTime(minutes + 1);
+            expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), minutes * 2);
+            expect(props.getMessageCount).toHaveBeenCalledTimes(count);
+            minutes = minutes * 2;
+        }
+
+        // Exhaust all timers (there shouldn't be any left)
+        jest.runAllTimers();
+        // We exponentially back off checking for messages, starting at 2 min
+        // and stop after 32 minutes so it should happen 5 times total.
+        expect(props.getMessageCount).toHaveBeenCalledTimes(5);
+        // setTimeout happens 1 fewer since the original call to
+        // setupMessagePolling isn't counted here.
+        expect(setTimeout).toHaveBeenCalledTimes(4);
+    });
 });